mmdolze
ebf9565f17
DELAY_IOCALLS is configured. DELAY_IOCALLS is never selected automatically but has to be configured by the user anyway. Did not use writes to 0x80 as readings make me think this tries to delay by 1ms where we want 1us.
194 lines
5.6 KiB
C
194 lines
5.6 KiB
C
/** \file server/drivers/timing.h
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* Utility header file for timing functions
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*
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* Made by Guillaume Filion, moved from the HD44780 driver.
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*
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* From hd44780.c:
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* Modified July 2000 by Charles Steinkuehler to use one of 3 methods for delay
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* timing. I/O reads, gettimeofday, and nanosleep. Of the three, nanosleep
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* seems to work best, so that's what is set by default.
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*/
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/*-
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* This file is released under the GNU General Public License. Refer to the
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* COPYING file distributed with this package.
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*
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* Copyright (c) 2001 Guillaume Filion <gfk@logidac.com>
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* 2001 Joris Robijn <joris@robijn.net>
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* 2000 Charles Steinkuehler <cstein@newtek.com>
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*/
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#ifndef _TIMING_H
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#define _TIMING_H
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/*
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* Uncomment one of the lines below this paragraph to select your desired
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* delay generation mechanism.
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* Mechanism DELAY_NANOSLEEP seems to provide the best performance.
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* Mechanism DELAY_IOCALLS can be quite inaccurate.
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* Mechanism DELAY_AUTOSELECT lets the system determine a mechanism, and is
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* the default.
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*/
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#define DELAY_AUTOSELECT
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//#define DELAY_GETTIMEOFDAY
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//#define DELAY_NANOSLEEP
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//#define DELAY_IOCALLS
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#include <string.h>
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#include <errno.h>
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#include <unistd.h>
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#ifdef HAVE_CONFIG_H
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# include "config.h"
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#endif
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/* Autoselect... Does this always work well ? */
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#ifdef DELAY_AUTOSELECT
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# if defined HAVE_SCHED_H && defined HAVE_SCHED_SETSCHEDULER
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# define DELAY_NANOSLEEP
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# else
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# define DELAY_GETTIMEOFDAY
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# endif
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#endif
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/* Include the correct time.h stuff (regardless of selected mechanism) */
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#if TIME_WITH_SYS_TIME
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# include <sys/time.h>
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# include <time.h>
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#else
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# if HAVE_SYS_TIME_H
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# include <sys/time.h>
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# else
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# include <time.h>
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# endif
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#endif
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/* Only one alternate delay method at a time, please ;-) */
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#if defined DELAY_GETTIMEOFDAY
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# undef DELAY_NANOSLEEP
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# undef DELAY_IOCALLS
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#elif defined DELAY_IOCALLS && defined HAVE_PCSTYLE_LPT_CONTROL
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# undef DELAY_GETTIMEOFDAY
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# undef DELAY_NANOSLEEP
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# include "port.h"
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#else /* assume DELAY_NANOSLEEP */
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# undef DELAY_GETTIMEOFDAY
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# undef DELAY_IOCALLS
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# include <sched.h>
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#endif
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/*
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* Convenience macros for operations on timevals. These are usually defined
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* in sys/time.h. If your system does not have them, the defines from below
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* are used.
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*
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* NOTE: `timercmp' does not work for >= or <=.
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*/
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#ifndef timerisset
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# define timerisset(tvp) ((tvp)->tv_sec || (tvp)->tv_usec)
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#endif
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#ifndef timerclear
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# define timerclear(tvp) ((tvp)->tv_sec = (tvp)->tv_usec = 0)
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#endif
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#ifndef timercmp
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# define timercmp(a, b, CMP) \
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(((a)->tv_sec == (b)->tv_sec) ? \
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((a)->tv_usec CMP (b)->tv_usec) : \
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((a)->tv_sec CMP (b)->tv_sec))
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#endif
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#ifndef timeradd
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# define timeradd(a, b, result) \
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do { \
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(result)->tv_sec = (a)->tv_sec + (b)->tv_sec; \
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(result)->tv_usec = (a)->tv_usec + (b)->tv_usec; \
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if ((result)->tv_usec >= 1000000) \
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{ \
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++(result)->tv_sec; \
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(result)->tv_usec -= 1000000; \
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} \
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} while (0)
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#endif
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#ifndef timersub
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# define timersub(a, b, result) \
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do { \
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(result)->tv_sec = (a)->tv_sec - (b)->tv_sec; \
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(result)->tv_usec = (a)->tv_usec - (b)->tv_usec; \
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if ((result)->tv_usec < 0) { \
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--(result)->tv_sec; \
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(result)->tv_usec += 1000000; \
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} \
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} while (0)
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#endif
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/**
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* Do necessary initialization for the selected waiting method.
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* \return 0 if successful, -1 on error.
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*/
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static inline int
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timing_init()
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{
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#if defined DELAY_NANOSLEEP
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/* Change to Round-Robin scheduling for nanosleep */
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{
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/* Set priority to 1 */
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struct sched_param param;
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param.sched_priority=1;
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if (( sched_setscheduler(0, SCHED_RR, ¶m)) == -1) {
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return -1;
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}
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}
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#elif defined DELAY_IOCALLS
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if (port_access(0x3BD) == -1) {
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return -1;
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}
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#endif
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return 0;
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}
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/**
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* Delay operation for some time using either gettimeofday (more or less an
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* active waiting loop), nanosleep, or an I/O call.
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* \param usecs Microsecond to pause
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*/
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static inline void
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timing_uPause(int usecs)
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{
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#if defined DELAY_GETTIMEOFDAY
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struct timeval current_time,delay_time,wait_time;
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/* Get current time first thing */
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gettimeofday(¤t_time,NULL);
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/* Calculate when delay is over */
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delay_time.tv_sec = 0;
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delay_time.tv_usec = usecs;
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timeradd(¤t_time,&delay_time,&wait_time);
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do {
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gettimeofday(¤t_time,NULL);
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} while (timercmp(¤t_time,&wait_time,<));
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#elif defined DELAY_NANOSLEEP
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struct timespec delay_time,remaining;
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delay_time.tv_sec = 0;
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delay_time.tv_nsec = usecs * 1000;
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while ( nanosleep(&delay_time,&remaining) == -1 )
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{
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delay_time.tv_sec = remaining.tv_sec;
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delay_time.tv_nsec = remaining.tv_nsec;
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}
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#else /* using I/O timing */
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int i;
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for (i = 0; i < usecs; ++i)
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port_in(0x3BD); /* Assuming every port I/O takes 1us */
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#endif
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}
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#endif /* _TIMING_H */
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